Imprint method

ABSTRACT

The present invention provides an imprint apparatus comprising a deforming unit configured to deform a pattern surface by applying a force to a mold, a measuring unit configured to measure a deformation amount of the pattern surface, a control unit configured to control the measuring unit to measure the deformation amount in each of a plurality of states in which a plurality of the forces are applied to the mold, a calculation unit configured to calculate a rate of change in the deformation amount as a function of a change in the force applied to the mold, and a calibration unit configured to calibrate a control profile describing a time in the imprint process, and the force applied to the mold, based on the rate of change in the deformation amount.

TECHNICAL FIELD

The present invention relates to an imprint apparatus and a method ofmanufacturing an article.

BACKGROUND ART

The imprint technique is attracting a great deal of attention as one ofnano-lithography techniques for volume production of, for example,magnetic storage media and semiconductor devices. In the imprinttechnique, a pattern is transferred onto a substrate such as a siliconwafer or a glass plate using, as an original, a mold having a finepattern formed on it.

An imprint apparatus which uses such an imprint technique presses a moldagainst a substrate via a resin (imprint material) supplied on thesubstrate, and cures the resin in this state. The imprint apparatus thenseparates the mold from the cured resin to transfer the pattern of themold onto the substrate. At this time, it is necessary to prevent lossof the pattern transferred onto the substrate. To meet this requirement,Japanese Patent Laid-Open Nos. 2009-536591 and 2009-517882 proposetechniques of deforming (curving) the mold so as to form a convexsurface that bulges toward the substrate in bringing the mold intocontact with the resin on the substrate, or separating the mold from thecured resin.

An imprint apparatus generally uses a plurality of molds, each of whichis applied with a predetermined force to deform each mold in the sameamount (in a predetermined amount) in a mold deforming operation (thatis, in an imprint process). However, the thickness of each mold variesdue, for example, to manufacturing errors and dimension errors.Therefore, when the force to be applied to each mold remains the same,the deformation amount of each mold in an imprint process varies. As aresult, the dimension and shape of the pattern transferred onto thesubstrate vary across individual molds, or loss is generated in thetransferred pattern.

SUMMARY OF INVENTION

The present invention provides a technique advantageous in terms ofpattern transfer accuracy in an imprint apparatus.

According to one aspect of the present invention, there is provided animprint apparatus which performs an imprint process of curing a resin ona substrate while a mold having a pattern surface on which a pattern isformed is pressed against the resin, and separating the mold from thecured resin, thereby transferring the pattern onto the substrate, theapparatus comprising: a deforming unit configured to deform the patternsurface by applying a first force to the mold; a first measuring unitconfigured to measure a deformation amount of the pattern surface; acontrol unit configured to control the first measuring unit to measurethe deformation amount of the pattern surface in each of a plurality ofstates in which a plurality of first forces are applied to the mold bythe deforming unit; a calculation unit configured to calculate a rate ofchange in deformation amount of the pattern surface as a function of achange in first force applied to the mold by the deforming unit, basedon a relationship between each of the plurality of first forces appliedto the mold and the deformation amount of the pattern surfacecorresponding to each of the plurality of first forces; and acalibration unit configured to calibrate a first control profiledescribing a time in the imprint process, and a first force to beapplied to the mold by the deforming unit, based on the rate of changein deformation amount of the pattern surface calculated by thecalculation unit, so that the deformation amount of the pattern surfacein the imprint process becomes a target amount.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a view showing the configuration of an imprint apparatusaccording to the first embodiment of the present invention;

FIG. 2 is a view showing the imprint apparatus according to the firstembodiment of the present invention before a mold is pressed against aresin on a substrate;

FIG. 3 is a view showing the imprint apparatus according to the firstembodiment of the present invention while the mold is pressed againstthe resin on the substrate;

FIG. 4 shows graphs of first control profiles describing therelationships between the time during an imprint process, and theZ-position of a holding unit and the pressure in a chamber,respectively, at this time;

FIG. 5 is a sectional view of a mold;

FIG. 6 is a graph showing the relationship between the thickness of themold and the deformation amount of a pattern surface;

FIG. 7 is a graph showing the relationship between the pressure in thechamber and the deformation amount of the pattern surface in the imprintapparatus according to the first embodiment of the present invention;

FIG. 8 is a graph showing the result of calculating the relationshipbetween the pressure in the chamber and the deformation amount of thepattern surface;

FIG. 9 is a view showing the configuration of an imprint apparatusaccording to the second embodiment of the present invention; and

FIG. 10 is a graph showing the relationship between the pressure in achamber and the distortion of a pattern surface in the imprint apparatusaccording to the second embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

Exemplary embodiments of the present invention will be described belowwith reference to the accompanying drawings. Note that the samereference numerals denote the same members throughout the drawings, anda repetitive description thereof will not be given.

First Embodiment

An imprint apparatus 100 according to the first embodiment of thepresent invention will be described with reference to FIG. 1. Theimprint apparatus 100 performs an imprint process of curing a resin on asubstrate while a mold having a pattern formed on it is pressed againstthe resin, and separating the mold from the cured resin, therebytransferring the pattern onto the substrate.

The imprint apparatus 100 includes a holding unit 4 which holds a mold5, a structure 11, a substrate stage 1, and a substrate chuck 2. Theimprint apparatus 100 also provides a deforming unit 21, first measuringunit 22, control unit 23, calculation unit 24, and calibration unit 25,as a control system 20 which performs an imprint process upon deformingthe mold 5.

The mold 5 is held by the holding unit 4, and has a pattern surface 6 onwhich a pattern is formed. The surface of the mold 5, which is oppositeto the pattern surface 6, contacts the holding surface of the holdingunit 4. Also, the mold 5 has a concave portion formed by drilling itssurface on the side of the holding surface so as to reduce the thicknessof the portion in which the pattern is formed (pattern surface 6). Byreducing the thickness of the portion in which the pattern is formed,that is, the pattern surface 6, the pattern surface 6 of the mold 5 caneasily deform when a pressure is applied to a chamber 3 (to be describedlater).

The concave portion formed in the mold 5 forms a practically airtightlysealed space in cooperation with the holding surface of the holding unit4. The space formed by the concave portion in the mold 5, and theholding surface of the holding unit 4 will be referred to as a chamber 3hereinafter. A pipe 7 is formed in the holding unit 4 to communicatewith the chamber 3. The pipe 7 is connected to the deforming unit 21.The deforming unit 21 is implemented by a pressure controller including,for example, a servo valve and a switching valve for switching between asupply source which supplies compressed air to the chamber 3 and thatwhich evacuates the chamber 3 to a vacuum. The deforming unit 21 appliesa first force to the mold 5 using the pressure in the chamber 3.

The holding unit 4 is attached to the structure 11 and driven in theZ-direction (vertically) by a driving source and a control mechanism(neither is shown) to bring a substrate 8 and the mold 5 close to eachother or separate them from each other. The substrate 8 is held by thesubstrate stage 1, which is capable of moving in the X- andY-directions, through the substrate chuck 2.

In an imprint process, the imprint apparatus 100 deforms the mold 5using the pressure in the chamber 3 so that the pattern surface 6 formsa convex surface that bulges toward the substrate 8.

FIGS. 2 and 3 show the sequence of a series of operations until the mold5 is pressed against a resin 12 on the substrate 8 in an imprintprocess. Referring to FIG. 2, the substrate 8 dispensed with the resin12 is arranged below the mold 5. In this state, the deforming unit 21applies a pressure to the chamber 3 to deform the mold 5 so that thepattern surface 6 forms a convex shape to bulge toward the substrate 8.At this time, the pattern surface 6 of the mold 5 is not in contact withthe resin 12 on the substrate 8. In pressing the mold 5 against theresin 12 on the substrate 8, first, the holding unit 4 is lowered in theZ-direction to bring the central portion of the pattern surface 6 of themold 5 into contact with the resin 12 on the substrate 8. Upon thisoperation, the control mode of the holding unit 4 is switched fromposition control to force control. The pattern surface 6 of the mold 5is continuously brought into contact with the resin 12 while thepressure in the chamber 3 is gradually weakened outwards from itscentral portion. Eventually, the deforming unit 21 changes the pressurein the chamber 3 to the degree that the pattern surface 6 of the mold 5becomes flat, as shown in FIG. 3. In this state, the process waits untilthe pattern of the mold 5 is filled with the resin 12. After the patternof the mold 5 is filled with the resin 12, the resin 12 is irradiatedwith ultraviolet rays to cure it. After the resin 12 cures upon beingirradiated with ultraviolet rays, the mold 5 is separated from the curedresin 12. In separating the mold 5 from the cured resin 12, the curedresin 12 and the pattern surface 6 have adhered to each other, so thepattern surface 6 deforms into a convex surface that bulges toward thesubstrate 8 as the mold 5 is pulled toward the substrate 8. Hence, inseparating the mold 5 from the cured resin 12, the deforming unit 21gradually weakens the pressure in the chamber 3.

In the above-mentioned imprint process, the characteristics of drivingcontrol of the holding unit 4 in the Z-direction and pressure control ofthe chamber 3 are stored in the imprint apparatus 100 as controlprofiles in advance. FIG. 4 shows graphs of control profiles describingthe relationships between the time and the Z-position of the holdingunit 4 and the pressure in the chamber 3, respectively. Referring toFIG. 4, a graph 41 shows a control profile describing the relationshipbetween the time and the Z-position of the holding unit 4, and a graph42 shows a control profile describing the relationship between the timeand the pressure in the chamber 3. Note that the time of imprinting isdefined from the start of lowering the mold 5 in the Z-direction untilthe entire pattern surface of the mold 5 comes into contact with theresin 12 on the substrate 8. Also, the time of release is defined fromthe start of lifting the mold 5 in the Z-direction until the patternsurface of the mold 5 separates from the resin 12. At the time ofimprinting, when the Z-position of the holding unit 4 has a negativegradient, the chamber 3 is maintained at a predetermined pressure atwhich the pattern surface 6 of the mold 5 deforms into a convex shape tobulge toward the substrate 8. In the period from when the centralportion of the pattern surface 6 of the mold 5 is brought into contactwith the resin 12 on the substrate 8 until this central portion ispressed against the resin 12, the mold 5 and the resin 12 on thesubstrate 8 assume a state shown in FIG. 3, in which the pressure in thechamber 3 gradually weakens while the Z-position of the holding unit 4remains the same. At the time of release, the mold 5 is separated fromthe cured resin 12, so the Z-position of the holding unit 4 has apositive gradient, and the pressure in the chamber 3 gradually weakensat that time. Loss of the pattern transferred onto the substrate 8 canbe prevented by controlling the pressure in the chamber 3 at the time ofimprinting or release in this way.

The imprint apparatus 100 generally uses a plurality of exchangeablemolds 5. Each of the plurality of molds 5 transmits ultraviolet light,and is therefore manufactured by machining silica glass. Hence, thethickness of each mold 5 varies due, for example, to manufacturingerrors and dimension errors. This means that when the first controlprofile of each mold 5 remains the same, the deformation amount of thepattern surface 6 (the difference in shape of the central portion of thepattern surface 6 when the pattern surface 6 is flat and when it hasdeformed) varies across individual molds 5 due to factors associatedwith the thickness (its difference) of each mold 5. As a result, thedimension and shape of the pattern transferred onto the substrate 8 alsovary across individual molds 5. When a mold 5 having a cross-sectionalshape as shown in, for example, FIG. 5 is used, a deformation amountWmax of the pattern surface 6 as a function of the thickness of the mold5 upon a change in pressure of the chamber 3 is given by:

${W\;\max} = {\frac{P \cdot R^{4}}{64} \cdot \frac{12\left( {1 - v^{2}} \right)}{E \cdot t^{3\;}}}$where 2R is the diameter of the concave portion in the mold 5 shown inFIG. 5 and is 64 mm, t is the thickness of the mold 5 and is 1.0 to 1.2mm, P is the pressure in the chamber 3 and is 10, 30, and 50 kPa, E isthe longitudinal elastic modulus of the mold 5 and is 71,500 N/mm², andv is the Poisson's ratio and is 0.335.

FIG. 6 shows the relationship between the thickness of the mold 5 andthe deformation amount of the pattern surface 6. As can be seen fromFIG. 6, when the thickness t of the mold 5 changes while the pressure Pin the chamber 3 remains the same, the deformation amount Wmax of thepattern surface 6 changes in inverse proportion to the cube of thethickness t of the mold 5. This change becomes more conspicuous as thepressure P in the chamber 3 increases. In this manner, even when theerror of the thickness of the mold 5 is controlled to fall within atolerance of Target Thickness±0.025 mm, an error occurs in thedeformation amount of the pattern surface 6 in each mold 5.

For this reason, the imprint apparatus 100 provides the deforming unit21, first measuring unit 22, control unit 23, calculation unit 24, andcalibration unit 25, as the control system 20.

In this embodiment, the deforming unit 21 changes the pressure in thechamber 3 to change a first force applied to the mold 5. The controlunit 23 controls the first measuring unit 22 to measure the deformationamount of the pattern surface 6 while each of a plurality of firstforces is applied to the mold 5 by the deforming unit 21. Thecalculation unit 24 calculates the rate of change in deformation amountof the pattern surface 6 as a function of the change in first forceapplied to the mold 5, based on the relationship between each of aplurality of first forces applied to the mold 5 and the deformationamount of the pattern surface 6 corresponding to each of the pluralityof first forces. Based on the rate of change in deformation amount ofthe pattern surface 6, the calibration unit 25 calibrates a firstcontrol profile describing the relationship between the time in animprint process and the first force to be applied to the mold 5 by thedeforming unit 21 at this time, so that the deformation amount of thepattern surface 6 becomes a target amount. The deforming unit 21 appliesa first force to the mold 5 based on the first control profilecalibrated by the calibration unit 25. In this embodiment, the firstmeasuring unit 22, control unit 23, calculation unit 24, and calibrationunit 25 can set the deformation amount of the pattern surface 6 of eachmold 5 to a target amount in an imprint process even if the thickness ofeach mold 5 varies.

An example of an imprint process by the imprint apparatus 100 accordingto the first embodiment will be described below. In this case, a mold 5actually used in an imprint process is defined as a mold A. Also, thepressure in the chamber 3 is regarded to be equivalent to the forceapplied to the mold A.

While the pressure in the chamber 3 is set to a first pressure P1 by thedeforming unit 21, the first measuring unit 22 measures a deformationamount W1 of the pattern surface 6 of the mold A. Similarly, the firstmeasuring unit 22 measures a deformation amount W2 of the patternsurface 6 while the pressure in the chamber 3 is set to a secondpressure P2, and a deformation amount W3 of the pattern surface 6 whilethe pressure in the chamber 3 is set to a third pressure P3. FIG. 7shows the relationship between the three pressures P1, P2, and P3 in thechamber 3, and the corresponding deformation amounts W1, W2, and W3 ofthe pattern surface 6. FIG. 7 shows the pressure in the chamber 3 on theabscissa, and the deformation amount of the pattern surface 6 on theordinate.

FIG. 8 shows the result of calculating by simulation the deformationamount (target amount) of the pattern surface 6 of a reference mold(thickness: 1.1 mm) when a pressure is applied to the chamber 3. Thepressure in the chamber 3 and the deformation amount of the patternsurface 6 have an approximately linear relationship (proportionalrelationship). Accordingly, since the three actual measurement valuesshown in FIG. 7 can be represented by linear approximation, thecalculation unit 24 can calculate, from these three actual measurementvalues, a rate of change (approximate line) Ck′ of the deformationamount of the pattern surface 6 as a function of the change in pressureof the chamber 3. Also, the calculation unit 24 can calculate thepressure in the chamber 3, which is required to set the deformationamount of the pattern surface 6 to a target amount, based on theapproximate line Ck′. This target amount is determined from thedeformation amount of the pattern surface 6 in an imprint process usingthe reference mold. In filling the pattern of the mold 5 with the resin12, the pattern surface 6 must be flat. The target amount for thedeformation amount of the pattern surface 6 at this time is on theX-axis shown in FIG. 7, that is, zero, so a pressure P0 in the chamber3, at which the deformation amount of the pattern surface 6 is zero, canbe calculated from the approximate line Ck′. Also, it is necessary todeform the pattern surface 6 into a convex shape until the mold 5 comesinto contact with the resin 12 on the substrate 8 at the time ofimprinting. Letting W0′ be the target amount for the deformation amountof the pattern surface 6 at this time, a pressure P0′ in the chamber 3,at which the deformation amount of the pattern surface 6 is set to thetarget amount W0′, can be calculated. Note that FIG. 7 shows thesimulation result of the reference mold, shown in FIG. 8, together withthe approximate line of the actual measurement value, which is definedas a line Ck.

The calibration unit 25 calibrates the first control program using theslope of the approximate line Ck′ calculated by the calculation unit 24,and the pressures P0 and P0′ in the chamber 3, so that the deformationamount of the mold A becomes the deformation amount (target amount) ofthe reference mold in an imprint process. Calibration of the firstcontrol profile will be explained with reference to the graph 42 shownin FIG. 4. A solid line indicates a first control profile correspondingto the reference mold, and a broken line indicates a first controlprofile corresponding to the mold A. Referring to FIG. 7, the pressurein the chamber 3, at which the deformation amount of the pattern surfaceof the mold A is set to the target amount W0′, is P0′, and itsdifference from the pressure of the chamber 3 when the deformationamount of the pattern surface of the reference mold is the target amountW0′ is ΔP. Hence, until the mold A comes into contact with the resin 12at the time of imprinting in FIG. 4, the force applied to the referencemold (that is, the force applied to the chamber 3) is set lower thanthat applied to the mold A by ΔP. AP can be calculated from the line Ckfor the reference mold and the approximate line Ck′ for the mold A.Similarly, in filling the pattern of the mold A with the resin 12, toflatten the pattern surface, the force applied to the mold A is setlower than that applied to the reference mold by P0. In the period fromwhen the mold A comes into contact with the resin 12 until the start offilling the pattern of the mold A with the resin 12 at the time ofimprinting, and at the time of release, the rate of change in forceapplied to the mold A (in pressure of the chamber 3) is changed based onthe slope of the approximate line Ck′.

In the first embodiment, the deformation amount of the pattern surface 6while each of a plurality of first forces is applied to the mold 5 ismeasured to obtain the relationship between each of the plurality offirst forces applied to the mold 5, and the deformation amount of thepattern surface 6 corresponding to each of the plurality of firstforces. The rate of change in deformation amount of the pattern surface6 as a function of the change in first force applied to the mold 5 iscalculated from this relationship. A first control profile describingthe relationship between the time in an imprint process, and the firstforce to be applied to the mold 5 at this time is calibrated based onthe calculated rate of change in deformation amount of the patternsurface 6. With this operation, even if the thickness of each mold 5varies, an imprint process can be performed upon deforming the patternsurface of each mold 5 as in the reference mold. Although the line Ckfor the reference mold is determined from the simulation result in thefirst embodiment, it may be determined from an actual measurement value.In this case, the line Ck may not pass through the origin. When thishappens, it is necessary to calibrate the first control profile inconsideration of the first force applied to the mold (the pressure inthe chamber 3) when the deformation amount of the pattern surface 6 ofthe reference mold is zero.

Second Embodiment

An imprint apparatus 200 according to the second embodiment of thepresent invention will be described with reference to FIG. 9. Theimprint apparatus 200 according to the second embodiment includes achange unit 26 and second measuring unit 27, in addition to theconstituent units of the imprint apparatus 100 according to the firstembodiment. Also, the imprint apparatus 200 controls not only thedeformation amount of a pattern surface 6 but also the distortion of thepattern surface 6 to target amounts. Note that the imprint apparatus 200according to the second embodiment has already calibrated the firstcontrol profile described in the first embodiment.

A plurality of alignment marks are formed on a mold 5. A plurality ofalignment marks are also formed on a substrate 8 for each shot region incorrespondence with the positions of the alignment marks on the mold 5.Note that the plurality of alignment marks formed on the substrate 8 canalso be substituted with a plurality of alignment marks formed on areference plate arranged on a substrate stage 1.

The change unit 26 changes the distortion of the pattern surface 6 byapplying a second force to the mold 5. An actuator such as apiezoelectric element is used as the change unit 26. By changing theamount of actuation of the actuator, a second force is applied from theside surface of the mold 5 so that the distortion of the pattern surface6 can be changed.

The second measuring unit 27 simultaneously detects the pluralities ofalignment marks formed on the mold 5 and substrate 8, respectively, andtherefore includes a plurality of detectors 9. The substrate stage 1 ismoved so that each alignment mark formed on the substrate 8 overlaps thecorresponding alignment mark formed on the mold 5 to allow each detector9 to detect the relative position between these corresponding alignmentmarks. The second measuring unit 27 measures the distortion of thepattern surface 6 of the mold 5 from the detection result (the relativeposition between the corresponding alignment marks) obtained by thedetector 9.

A control unit 23 controls not only a deforming unit 21 and firstmeasuring unit 22 together, as described in the first embodiment, butalso the deforming unit 21 and second measuring unit 27 together. Thecontrol unit 23 controls the second measuring unit 27 to measure thedistortion of the pattern surface 6 while each of a plurality of firstforces is applied to the mold 5 by the deforming unit 21.

A calculation unit 24 calculates not only the rate of change indeformation amount of the pattern surface 6, described in the firstembodiment, but also that in distortion of the pattern surface 6. Thecalculation unit 24 calculates the rate of change in distortion of thepattern surface 6 as a function of the change in first force applied tothe mold 5, based on the relationship between each of a plurality offirst forces applied to the mold 5 and the distortion of the patternsurface 6 corresponding to each of the plurality of first forces.

A calibration unit 25 calibrates not only the first control profile,described in the first embodiment, but also a second control profile.The second control profile represents the relationship between the timein an imprint process, and the second force to be applied to the mold 5by the change unit 26 at this time. The second control profile iscalibrated based on the rate of change in distortion of the patternsurface 6 calculated by the calculation unit 24, so that the distortionof the pattern surface 6 becomes a target amount in an imprint process.With this operation, even if the thickness of each mold 5 varies, animprint process can be performed upon calibrating the distortion of thepattern surface 6 of each mold 5 to a target amount.

An example of an imprint process by the imprint apparatus 200 accordingto the second embodiment will be described below. In this case, a mold 5actually used in an imprint process is defined as a mold A. Also, theamount of actuation of the actuator is regarded to be equivalent to thesecond force applied to the mold A. Note that the imprint apparatus 200according to the second embodiment has already calibrated the firstcontrol profile as in the imprint apparatus 100 according to the firstembodiment.

While the pressure in a chamber 3 is set to a first pressure P1 by thedeforming unit 21, the second measuring unit 27 measures a distortion D1of the pattern surface 6 of the mold A. Similarly, the second measuringunit 27 measures a distortion D2 of the pattern surface 6 while thepressure in the chamber 3 is set to a second pressure P2, and adistortion D3 of the pattern surface 6 while the pressure in the chamber3 is set to a third pressure P3. FIG. 10 shows the relationship betweenthe three pressures P1, P2, and P3 in the chamber 3, and thecorresponding distortions D1, D2, and D3 of the pattern surface 6. FIG.10 shows the pressure in the chamber 3 on the abscissa, and thedistortion of the pattern surface 6 on the ordinate. Note that thedistortion means the deformation amount (including magnification, skew,and other trapezoidal components) of the pattern surface 6 of the mold 5in the in-plane direction. Although the pressures P1, P2, and P3 in thechamber 3 are the same as those described in the first embodiment, theformer may be different from the latter.

The distortion (target amount) of the pattern surface 6 of a referencemold (thickness: 1.1 mm) when a pressure is applied to the chamber 3 todeform the pattern surface 6 is calculated by simulation. As a result,the pressure in the chamber 3 and the distortion of the pattern surface6 have an approximately linear relationship. Accordingly, thecalculation unit 24 can calculate a rate of change (approximate line)Dk′ of the distortion of the pattern surface 6 as a function of thechange in pressure of the chamber 3 by approximating the three actualmeasurement values shown in FIG. 10 by a line. Also, the calculationunit 24 can calculate the distortion of the pattern surface 6 at thepressure in the chamber 3, at which the deformation amount of thepattern surface 6 is set to the target amount, based on the approximateline. As described in the first embodiment, the pressure in the chamber3, at which the deformation amount of the pattern surface 6 is set tothe target amount, is P0 and P0′, so the distortion of the patternsurface 6 is D0 and D0′ when the pressure in the chamber 3 is P0 andP0′, respectively. Note that FIG. 10 shows the simulation result of thereference mold together with the approximate line Dk′ of the actualmeasurement value, which is defined as a line Dk.

The calibration unit 25 calibrates the second control profile using theapproximate line Dk′ calculated by the calculation unit 24, and thedistortions D0 and D0′ of the pattern surface 6, so that the distortionof the pattern surface 6 becomes a target amount in an imprint process.Until the mold 5 comes into contact with the resin 12 at the time ofimprinting, the pressure P0′ is applied to the chamber 3, and thedistortion of the pattern surface 6 of the mold A is D0′. Hence, thedistortion of the pattern surface 6 of the reference mold is calculatedfrom the line Dk when the chamber 3 has the pressure P0′, and itsdifference ΔD0′ from the distortion D0′ is corrected by the amount ofactuation of the actuator. Similarly, in filling the pattern of the mold5 with the resin 12, the pressure P0 is applied to the chamber 3, andthe distortion of the pattern surface 6 of the mold A is D0. Hence, thedistortion of the pattern surface 6 of the reference mold is calculatedfrom the line Dk when the chamber 3 has the pressure P0, and itsdifference ΔD0 from the distortion D0 is corrected by the amount ofactuation of the actuator. In the period from when the mold 5 comes intocontact with the resin 12 until the start of filling the pattern of themold A with the resin 12 at the time of imprinting, and at the time ofrelease, the rate of change in amount of actuation of the actuator ischanged based on the slope of the approximate line Dk′.

In the second embodiment, the distortion of the pattern surface 6 ismeasured while each of a plurality of second forces is applied to themold 5. Also, the relationship between each of a plurality of secondforces applied to the mold 5 and the distortion of the pattern surface 6corresponding to each of the plurality of second forces is obtained. Therate of change in distortion of the pattern surface 6 as a function ofthe change in second force applied to the mold 5 is calculated from thisrelationship. A second control profile describing the relationshipbetween the time in an imprint process, and the second force to beapplied to the mold 5 at this time is calibrated based on the calculatedrate of change in distortion of the pattern surface 6. With thisoperation, even if the thickness of each mold 5 varies, an imprintprocess can be performed using the same distortion as in the referencemold. Although the line Dk for the reference mold is determined from thesimulation result in the second embodiment, it may be determined from anactual measurement value. Also, although the imprint apparatus 200according to the second embodiment has already calibrated the firstcontrol profile as in the imprint apparatus 100 according to the firstembodiment, it may simultaneously calibrate the first and second controlprofiles.

Embodiment of Method of Manufacturing Article

A method of manufacturing an article according to an embodiment of thepresent invention is suitable for manufacturing various articlesincluding a microdevice such as a semiconductor device and an elementhaving a microstructure. This method includes a step of forming apattern on a resin, dispensed on a substrate, using the above-mentionedimprint apparatus (a step of performing an imprint process on asubstrate), and a step of developing the substrate having the patternformed on it in the forming step. This method also includes subsequentknown steps (for example, oxidation, film formation, vapor deposition,doping, planarization, etching, resist removal, dicing, bonding, andpackaging). The method of manufacturing an article according to thisembodiment is more advantageous in terms of at least one of theperformance, quality, productivity, and manufacturing cost of an articlethan the conventional method.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2012-024521 filed on Feb. 7, 2012, which is hereby incorporated byreference herein in its entirety.

The invention claimed is:
 1. An imprint method of forming a pattern ofan imprint material on a substrate in an imprint apparatus using a moldhaving a pattern surface, the method comprising: measuring, in theimprint apparatus, a deformation amount of the pattern surface using ameasurement unit provided to the imprint apparatus, in each of aplurality of states in which a plurality of first forces are applied tothe mold; obtaining a rate of change in the deformation amount of thepattern surface as a function of a change in the first force applied tothe mold, based on a relationship between each of the plurality of firstforces applied to the mold and the deformation amount of the patternsurface corresponding to each of the plurality of first forces;obtaining a relationship between a first force applied to the mold and adistance from the substrate to the pattern surface, based on theobtained rate of change, so that the deformation amount of the patternsurface becomes a target amount; and applying the first force to themold in the forming the pattern of the imprint material, based on therelationship between the first force applied to the mold and thedistance from the substrate to the pattern surface.
 2. The methodaccording to claim 1, further comprising obtaining a relationship,between the first force applied to the mold and the distance from thesubstrate to the pattern surface, in a state in which the patternsurface of the mold is pressed against the imprint material on thesubstrate.
 3. The method according to claim 1, further comprisingobtaining a relationship, between the first force applied to the moldand the distance from the substrate to the pattern surface, in a statein which the pattern surface of the mold is separated from the patternof the imprint material.
 4. The method according to claim 1, wherein inthe measuring the deformation amount of the pattern surface, the patternsurface is deformed by a pressure in a chamber between a holding surfaceof holding the mold and the mold, and the measurement unit used for themeasuring of the deformation amount of the pattern surface is placed ona substrate stage which is for holding the substrate.
 5. The methodaccording to claim 1, further comprising obtaining a first force to beapplied to the mold by lowering a reference force set in advance, basedon the relationship between the first force applied to the mold and thedistance from the substrate to the pattern surface.
 6. A method ofmanufacturing an article, the method comprising: forming a pattern of animprint material on a substrate in accordance with the method accordingto claim 1; and processing the substrate, on which the pattern of theimprint material has been performed, wherein the article is formed fromthe processed substrate.
 7. The method according to claim 1, wherein thefunction whose rate of change is obtained is a linear function.
 8. Animprint method of forming a pattern of an imprint material on asubstrate in an imprint apparatus using a mold having a pattern surface,the method comprising: measuring, in the imprint apparatus, adeformation amount of the pattern surface using a measurement unitprovided to the imprint apparatus, in each of a plurality of states inwhich a plurality of first forces are applied to the mold; obtaining arate of change in the deformation amount of the pattern surface as afunction of a change in the first force applied to the mold, based on arelationship between each of the plurality of first forces applied tothe mold and the deformation amount of the pattern surface correspondingto each of the plurality of first forces; obtaining a relationshipbetween a first force applied to the mold and a distance from thesubstrate to the pattern surface, based on the obtained rate of change,so that the deformation amount of the pattern surface becomes a targetamount; applying the first force to the mold in the forming the patternof the imprint material, based on the relationship between the firstforce applied to the mold and the distance from the substrate to thepattern surface; changing a distortion of the pattern surface byapplying a second force to the mold; measuring, in each of the pluralityof states in which the plurality of first forces are applied to themold, the distortion of the pattern surface by detecting a relativeposition between an alignment mark on the mold and an alignment mark onthe substrate; obtaining a rate of change in the distortion of thepattern surface as a function of a change in the first force applied tothe mold, based on a relationship between each of the plurality of firstforces applied to the mold and the distortion of the pattern surfacecorresponding to each of the plurality of first forces, and obtaining asecond relationship between a second force applied to the mold and adistance from the substrate to the pattern surface, based on the rate ofchange in the distortion of the pattern surface, so that the distortionof the pattern surface becomes a target amount.
 9. The method accordingto claim 8, wherein in the changing the distortion of the patternsurface, a distortion of the pattern surface is changed by applying thesecond force to a side of the mold.
 10. The method according to claim 8,further comprising applying the second force to the mold in the formingthe pattern of the imprint material, based on the second relationshipbetween the second force applied to the mold and the distance from thesubstrate to the pattern surface.
 11. An imprint method of performing,in an imprint apparatus, an imprint process of bringing an imprintmaterial on a substrate into contact with a pattern surface of a mold,curing the imprint material, and separating the mold from the curedimprint material, thereby forming a pattern of the imprint material onthe substrate, the method comprising: measuring, in the imprintapparatus, a deformation amount of the pattern surface using ameasurement unit provided to the imprint apparatus, in each of aplurality of states in which a plurality of first forces are applied tothe mold; obtaining a rate of change in the deformation amount of thepattern surface as a function of a change in the first force applied tothe mold, based on a relationship between each of the plurality of firstforces applied to the mold and the deformation amount of the patternsurface corresponding to each of the plurality of first forces;obtaining a relationship between a first force applied to the mold and atime in the imprint process, based on the obtained rate of change, sothat the deformation amount of the pattern surface becomes a targetamount, and applying the first force to the mold in the imprint process,based on the relationship between the first force applied to the moldand the time in the imprint process.
 12. The method according to claim11, further comprising obtaining the relationship by changing areference relationship between a reference force applied to the mold asthe first force and a time in the imprint process so that the referenceforce is lowered.
 13. A method of manufacturing an article, the methodcomprising: forming a pattern of an imprint material on a substrate inaccordance with the method according to claim 11; and processing thesubstrate, on which the pattern of the imprint material has beenperformed, wherein the article is formed from the processed substrate.14. An imprint method of forming a pattern of an imprint material on asubstrate in an imprint apparatus using a mold having a pattern surface,the method comprising: measuring, in the imprint apparatus, adeformation amount of the pattern surface using a measurement unitprovided to the imprint apparatus, in each of a plurality of states inwhich a plurality of first forces are applied to the mold; obtaining arate of change in the deformation amount of the pattern surface as afunction of a change in the first force applied to the mold, based on arelationship between each of the plurality of first forces applied tothe mold and the deformation amount of the pattern surface correspondingto each of the plurality of first forces; and updating a control profileindicating a relationship between a first force applied to the mold anda distance from the substrate to the pattern surface, based on theobtained rate of change, so that the deformation amount of the patternsurface becomes a target amount.
 15. The method according to claim 14,wherein in the updating the control profile, the first force applied tothe mold is lowered.
 16. A method of manufacturing an article, themethod comprising: forming a pattern of an imprint material on asubstrate in accordance with the method according to claim 14; andprocessing the substrate, on which the pattern of the imprint materialhas been performed, wherein the article is formed from the processedsubstrate.
 17. An imprint method of performing an imprint process, in animprint apparatus, of bringing an imprint material on a substrate intocontact with a pattern surface of a mold, curing the imprint material,and separating the mold from the cured imprint material, thereby forminga pattern of the imprint material on the substrate, the methodcomprising: measuring, in the imprint apparatus, a deformation amount ofthe pattern surface using a measurement unit provided to the imprintapparatus, in each of a plurality of states in which a plurality offirst forces are applied to the mold; obtaining a rate of change in thedeformation amount of the pattern surface as a function of a change inthe first force applied to the mold, based on a relationship betweeneach of the plurality of first forces applied to the mold and thedeformation amount of the pattern surface corresponding to each of theplurality of first forces; and updating a control profile indicating arelationship between a first force applied to the mold and a time in theimprint process, based on the obtained rate of change, so that thedeformation amount of the pattern surface becomes a target amount. 18.The method according to claim 17, wherein in the updating the controlprofile, the first force applied to the mold is lowered.
 19. A method ofmanufacturing an article, the method comprising: forming a pattern of animprint material on a substrate in accordance with the method accordingto claim 17; and processing the substrate, on which the pattern of theimprint material has been performed, wherein the article is formed fromthe processed substrate.